Tachometers are known for aircraft wheels that are mounted on axles to turn about axes of rotation. A tachometer comprises a stationary part for securing to the axle and a rotary part for being rotated by the wheel. One of the parts, generally the stationary part, includes a remote sensor adapted to co-operate with an indicator element carried by the other part in order to generate information about the speed of rotation of the wheel. For example the sensor may be of the variable reluctance type.
Such a sensor is known from document US 2001/0052258. The stationary and rotary parts comprise portions that extend facing each other in a radial direction, the remote sensor and the indicator element being carried by said portions so as to be in register with each other in a radial direction. In this case, the portion of the rotary part that carries the indicator element extends around the portion of the stationary part that carries the remote sensor.
It is thus necessary to reserve enough space beyond the end of the axle to be able to install the sensor and the indicator element, thereby increasing the bulkiness of the tachometer.